This invention relates to electrical output peak detecting apparatus and particularly such apparatus for use with analytical instruments. Apparatus for detecting electrical output peaks are commonly known. However, most of these apparatus provide erroneous peak indications when the electrical output includes noise. Otherwise, prior art apparatus avoid the affects of noise by time delaying the indication of peaks but this technique adversely affects the accuracy of peak detection. Although accuracy may be compromised in some peak detection applications, such compromise must be generally avoided in analytical instruments and especially instruments for spectral analysis wherein the electrical output thereof relates to the analyzed parameter which is dependent on a time varying spectral parameter.